Create a new wrapper for `requests`.

The wrapper function `request` in module `robottelo.api.client` is intended to
replace the similar wrapper function in `robottelo.api.base`.
Add unit tests for module robottelo.api.client
Add wrappers for more requests functions

Add wrappers for the following `requests` functions:

* head
* get
* post
* put
* patch
* delete

Take logging code and place it in a separate function. Make the logging function
capable of accepting more inputs and make its output nicer to read.
Write tests for module robottelo.api.client

Make tests for all untested code in target module. Fix a bug which was found
while writing tests.
Add new modules to API docs.

Add the following modules to the API docs:

* `robottelo.api.client`
* `tests.test_robottelo_api_client`

Also: fix a bug in `docs/api/tests.robottelo.rst`.
Provide more data to logging functions
Merge pull request #919 from Ichimonji10/requests-wrapper

Make a better `requests` wrapper
Add entity modeling and fields

Also define a basic entity for Host
Merge pull request #920 from elyezer/records

Add `Host` entity and underlying models
Better test `robottelo.common.ssh._get_connection`

Do not actually attempt to create SSH connections when testing
`_get_connection`. Instead, mock up `paramiko.SSHClient` and intercept calls to
methods like `connect` and `close`.
Make pylint happy

Most of pylint's warnings were spurious, but at least one set of warning was
valid: the attribute-defined-outside-init warning.
Rename module robottelo.models to robottelo.orm

This renaming has been done for the sake of clarity. Module robottelo.orm
contains components for mapping Python classes to Satellite entities, and module
robottelo.entities contains complete mappings of Python classes to Satellite
entities.

Also:

* Fix imports in module robottelo.entities to accomodate the rename
* Flesh out docstrings in module robottelo.entities

Related to #916
Merge pull request #922 from Ichimonji10/ssh-tests

Better test `robottelo.common.ssh._get_connection`
Merge pull request #923 from Ichimonji10/api-test-plumbing

Rename module robottelo.models to robottelo.orm